I've cancelled my subscription yesterday, conveniently it was about to renew at the end of the week, so I have a few days to migrate from Proton, here's what I'm thinking of, but I'd love to hear what other people are switching to
Running apps directly on Linux is like cooking in a shared kitchen where everyone shares the same spice rack. If one app needs an updated spice that breaks the recipe, your whole kitchen suffers.
Docker is like giving every app its own private kitchen pod with all its exact ingredients pre-packaged inside. Nothing leaks out, nothing interferes with the rest of your system, and if an app breaks, you just throw the whole pod away and start fresh without touching your main computer.
Once you get used to docker, you can stand up 20 apps in a night with standard configs and it all just works.
Later on, if you start really homelabbing it, you can stand up 3 small computers and cluster them to keep a copy of each container you're using up. If one of the boxes go down, they just shuffle and start the container on other nodes.